BNSF 938810 BDS-200 Ballast Distribution System with BNSF 938809 BDS-100 work together to remove old ballast and insert new ballast on pre-existing track. Plasser American built these units that work in tandem. Units were parked at BNSF's Denver Diesel Shop likely being serviced. BNSF Brush Line (Denver east towards Brush, CO) is undergoing extensive maintenance and lengthening sidings at Crest, Roggen and Tonneville (Lochbuie, CO).